Sift together flour, sugar and salt. Grate butter into the flour mixture, using the large hole-side of a box grater. Using your finger tips only, and working very quickly, rub the fat into the flour until the mixture resembles bread crumbs. Set aside.

Lightly beat the egg yolks with the almond extract (if using) and quickly mix into the flour mixture. Keep mixing while dribbling in the water, only adding enough to form a cohesive and slightly sticky dough.

Form the dough into a disc, wrap in cling and refrigerate for at least 30 minutes